5134 MOLECULAR MEDICINE REPORTS 14: 5134-5140, 2016 Chromosome 10q26 deletion syndrome: Two new cases and a review of the literature SHAOBIN LIN*, YI ZHOU*, QUN FANG, JIANZHU WU, ZHIQIANG ZHANG, YUANJUN JI and YANMIN LUO Fetal Medicine Center, Department of Obstetrics & Gynecology, The First Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510080, P.R. China Received September 29, 2015; Accepted October 6, 2016 DOI: 10.3892/mmr.2016.5864 Abstract. The current study presents the cases of two unrelated this syndrome present with symptoms that span a relatively patients with similar clinical features, including craniofacial extensive and heterogeneous phenotypic spectrum, although anomalies, developmental delay/intellectual disability and common clinical features, including craniofacial anomalies, cardiac malformations, that are consistent with chromosome developmental delay/intellectual disability (DD/ID), urinary 10q26 deletion syndrome. High-resolution single-nucleotide tract abnormalities, cardiac malformations and neurodevelop- polymorphism analysis revealed that 10q26 terminal deletions mental deficits, have been observed (4‑7). A pure distal 10q were present in these two patients. The locations and sizes deletion may be derived from familial or de novo structural of the 10q26 deletions in these two patients were compared variation and feature breakpoints at 10q25 or 10q26, although with the locations and sizes of 10q26 deletions in 30 patients interstitial or terminal deletions of large size, which are typi- recorded in the DECIPHER database and 18 patients charac- cally identified through conventional cytogenetic techniques, terized in previous studies through chromosomal microarray can also occur (4,8). Chromosomal microarray analysis (CMA), analysis. The clinical features and locations of the 10q26 dele- including the use of array comparative genome hybridization tions of these patients were reviewed in an attempt to map or and single‑nucleotide polymorphism (SNP) arrays, has been refine a critical region (CR) for phenotypes. Additionally, the recommended as the first‑tier test for individuals with DD/ID association between previously suggested CRs and phenotypic and/or congenital anomalies (9). CMA has been increasingly variability was discussed. The current study emphasize that a employed to refine the location and size of 10q26 deletions to distal 10q26 terminal deletion with a breakpoint at ~130 Mb improve understanding of genotype-phenotype correlations by may contribute to the common clinical features of 10q26 dele- identifying the minimal critical region (CR) or the smallest tion syndrome. region of deletion overlap associated with 10q26 deletion syndrome. Because this syndrome is a clinically heterogeneous Introduction disorder involving deletions of variable locations and sizes, the CR for 10q26 deletion syndrome and candidate genes for vari- The partial deletion of distal chromosome 10q was first able phenotypes remain unclear (10). Therefore, further studies reported by Lewandowski et al (1), and the existence of on patients with 10q26 deletions should be performed to eluci- a distinct chromosome 10q26 deletion syndrome (Online date the correlation between various phenotypes and the CR. Mendelian Inheritance in Man no. 609625) was then suggested The majority of examined cases of this syndrome were previ- due to consistent clinical findings (2‑4). This syndrome ously characterized using traditional techniques with limited is caused by a rare chromosomal abnormality, although resolution and low efficiency, including G‑banded karyotyping, ≥110 cases have been reported in the literature. Patients with fluorescence in situ hybridization and microsatellite marker genotyping, whereas few CMA-based molecular studies have been performed to investigate these cases. The current study attempted to refine a CR for this syndrome by performing a high-resolution molecular analysis of two unrelated patients Correspondence to: Professor Yanmin Luo, Fetal Medicine with pure terminal 10q26 deletions and comparing these Center, Department of Obstetrics & Gynecology, The First patients with patients with pure distal 10q deletions described Affiliated Hospital of Sun Yat-Sen University, 58 Zhongshan in previous CMA-based studies and the Database of Chromo- Road II, Guangzhou, Guangdong 510080, P.R. China E-mail: [email protected] somal Imbalance and Phenotype in Humans using Ensembl Resources (DECIPHER; https://decipher.sanger.ac.uk/), *Contributed equally specifically including patients from this database with deleted regions encompassed by the deleted regions of the two patients Key words: chromosome 10q26 deletion syndrome, critical region, examined in the current study and that presented without any genotype-phenotype correlation, SNP array other copy number variants or with other likely benign copy number variants. In addition, the phenotypic variability asso- ciated with CRs proposed in previous studies is discussed. LIN et al: TWO NOVEL CASES OF 10q26 DELETION SYNDROME 5135 Materials and methods DNA Blood Mini kit (Qiagen, Inc., Valencia, CA, USA) in accordance with the manufacturer's instructions. The SNP Case presentation. Patient 1, a 3-year-old female, was the array was performed according to the manufacturer's proto- second child of healthy, unrelated parents. Prenatal ultraso- cols. Briefly, genomic DNA samples (250 ng) were digested, nography indicated that duodenal atresia was present in the amplified and labeled. The DNA was hybridized to CytoScan fetus; therefore, the karyotyping of fetal blood was performed. HD array on the GeneChip Hybridization Oven 645 (Affyme- The fetal karyotype did not reveal any chromosomal abnor- trix, Inc., Santa Clara, CA, USA) at 50˚C for 16‑18 h, washed on malities (data not shown). Thus, the patient's parents continued the GeneChip Fluidics Station 450 (Affymetrix, Inc.), stained the pregnancy. Premature rupture of membranes occurred with Affymetrix GeneChip Stain Reagents, and scanned on at 36 weeks of gestation. Eventually, the parents opted for the GeneChip Scanner 3000 7G (Affymetrix, Inc.). The raw delivery by caesarian section. No neonatal respiratory distress data were analyzed using Chromosome Analysis Suite 3.0 was observed. The infant's weight and length at birth were software (ChAS 3.0; Affymetrix, Inc.) The CytoScan HD 2,420 g (<50th percentile) and 46 cm (<50th percentile), array contains more than 2.6 million markers for copy number respectively. Surgical therapy for duodenal atresia was analysis; 1,950,000 of these markers are unique, non‑polymor- administered following birth, and an operation to repair patent phic oligonucleotide probes, and 750,000 markers are SNP ductus arteriosus (PDA) was performed at 12 days after birth. probes used for genotyping. The average marker spacing is one The child was referred to the Fetal Medicine Center (The First probe every 1.1 kb, with a mean spacing of one probe every Affiliated Hospital of Sun Yat‑Sen University, Guangzhou) 1.7 kb on non‑gene backbones and one probe every 880 bp due to DD and mild ID observed at 3 years and 9 months in intragenic regions. Using ChAS 3.0 software (Affymetrix, of age. Milestones were significantly delayed, with walking Inc.), aberrations were filtered up to a minimal size of 100 kb, occurring at 3 years; current, the patient has no speech. The with ≥50 probe calls for deletions and duplications. patient's psychomotor development was significantly delayed. At the age of 3 years and 9 months, her weight, height and RefSeq and Database of Chromosome Imbalance and Pheno‑ head circumference were 9.6 kg (3rd percentile), 83.6 cm type in Humans Using Ensemble Resources (DECIPHER). (3rd percentile) and 46.5 cm (<10th percentile), respectively. The building of the human genome assembly was based on Cerebral magnetic resonance imaging did not reveal any Homo sapiens GRCH37/hg19. The gene content of the deleted abnormalities at this time. The patient exhibited certain region, including Online Mendelian Inheritance in Man genes craniofacial features of 10q26 deletion syndrome, including and RefSeq genes, was viewed and assessed with the UCSC a triangular-shaped face, hypertelorism, strabismus, a broadly Genome Browser (genome.ucsc.edu). The location and size of prominent nose and micrognathia. Palate anomalies were not the deleted region was compared with similar cases described observed. Her ear shape was normal, and audiometry indicated in previous CMA‑based studies and the DECIPHER (decipher. that she possessed normal hearing. An image of the patient sanger.ac.uk/). is not available in the present report. Patient 2, a 5-year-old female, was the second child of healthy, unrelated parents. She Results was born at full term by caesarian section due to a scarred maternal uterus. Her birth weight and length were 2,450 g Routine karyotyping of the two patients revealed similar (<3rd percentile) and 47 cm (<10th percentile), respectively. karyotypes of 46, XX, del(10) (q26) (Fig. 1A). The parents of Congenital heart defects (CHDs), including atrial septal defect the patients presented with normal chromosome karyotypes, and PDA, were observed by ultrasound examination during demonstrating the de novo origin of the examined 10q26 the neonatal period. At 3 months, the patient underwent an deletions. operation to address the CHDs. She walked and spoke her In the SNP array for Patient 1, a 10q terminal deletion with first word at 3 years. At the age of 5 years and 2 months, her a breakpoint